2013-03-04  Eric Botcazou  <ebotcazou@adacore.com>

	PR tree-optimization/56424
	* ipa-split.c (split_function): Do not set the RSO flag if result is
	not by reference and its type is not a register type.

	* gcc.dg/pr56424.c: New test.

--- gcc/ipa-split.c	(revision 196253)
+++ gcc/ipa-split.c	(working copy)
@@ -1309,7 +1309,9 @@ split_function (struct split_point *spli
      so return slot optimization is always possible.  Moreover this is
      required to make DECL_BY_REFERENCE work.  */
   if (aggregate_value_p (DECL_RESULT (current_function_decl),
-			 TREE_TYPE (current_function_decl)))
+			 TREE_TYPE (current_function_decl))
+      && (!is_gimple_reg_type (TREE_TYPE (DECL_RESULT (current_function_decl)))
+	  || DECL_BY_REFERENCE (DECL_RESULT (current_function_decl))))
     gimple_call_set_return_slot_opt (call, true);
 
   /* Update return value.  This is bit tricky.  When we do not return,
--- gcc/testsuite/gcc.dg/pr56424.c	2013-02-13 21:50:57.150673158 +0100
+++ gcc/testsuite/gcc.dg/pr56424.c	2013-03-04 12:59:24.133888683 +0100
@@ -0,0 +1,33 @@
+/* PR tree-optimization/56424 */
+
+/* { dg-do compile } */
+/* { dg-options "-O2 -fexceptions -fnon-call-exceptions" } */
+
+extern long double cosl (long double);
+extern long double sinl (long double);
+extern long double reml (long double, long double);
+
+long double my_cos (long double arg)
+{
+  return cosl (arg);
+}
+
+long double my_sin (long double arg)
+{
+  if (__builtin_fabs (arg) < 1.0)
+    return arg;
+
+  return sinl (arg);
+}
+
+long double my_cot (long double arg, long double cycle)
+{
+  long double t = reml (arg, cycle);
+  return my_cos (t) / my_sin (t);
+}
+
+long double my_tan (long double arg, long double cycle)
+{
+  long double t = reml (arg, cycle);
+  return my_sin (t) / my_cos (t);
+}